Power number

For Newton number, see also Kissing number in the sphere packing problem.

Template:For The power number N_p (also known as Newton number) is a commonly used dimensionless number relating the resistance force to the inertia force.

The power-number has different specifications according to the field of application. E.g., for stirrers the power number is defined as:<ref name="Seinfeld1991" />

<math> N_\mathrm{p} = \frac{P}{\rho n^{3} D^{5}} </math>

with

• P: power
• ρ: fluid density
• n: rotational speed in revolutions per second
• D: diameter of stirrer